If you are new to Asus products you may notice the system BIOS is a bit different, not to worry it is quite simple once you become familiar with it. To enter the system BIOS for your A7N8X press the Delete key before system post. (it's easiest to hold the delete key depressed right as you re-boot or power up) Additionally, and at this point, it is assumed that users that are willing to perform BIOS modifications have at-least a moderate knowledge of how software works- natively. The system Bios is only accessible using your keyboard, the mouse will not be functional. To select a field parameter simply scroll up or down or across using the arrow keys located on your keyboard  then press the enter key to view or change the parameter you have selected. If an area is grayed out it will not be user selectable.

ASUS has supplied a web page designed to help the novice user properly "flash" the system BIOS see it here.

Main Menu Page This is the first page you will see when entering the system Bios. From this page you can adjust the system clock, Error stop settings, and view the installed drive(s) placement. Additionally, by scrolling to the any of the available fields you may adjust according to your needs. A word about listed drives- it is preferable that upon first boot you select each field and then select "auto detect" this will help the Bios to identify your drive, it's location, and it's settings.

Advanced Menu Page This is the preface for entering into all the Advanced System Bios settings other than the above listed. There should be five selections available- as follows 1-Advanced Bios Features, 2-Advanced Chipset Features, 3-Integrated Peripherals, 4-Power Management, 5-Plug and Play and PCI Configuration.

Security Page This page allows a user to set a pass word for entering the Bios- default is off

Hardware This page does two things; first it monitors the motherboard and system hardware, temps etc. secondly, this is also where your Q-Fan control settings are located. You may adjust the Q-Fan settings as required- default is off. Q-Fan is a way of allowing the motherboard to vary your CPU cooling fan and other onboard system fans to a controlled rate. This is generally designed to help control fan noise and save some electrical power.

Exit Page The Exit page is used to save/discard your Bios settings or to replace the Bios settings to the system defaults in the event that you mistakenly created a situation that is causing boot errors. Additionally, when saving your Bios settings- upon exit a user may simply press F-10, this negates the necessity of using the Exit page.

Advanced Bios Page Listed below are a few settings from with in this area. I have listed the most necessary ones for initial system set up.

At this point Bios selection and settings are a HUGE forum that can not be simply answered by a beginners guide, the reason for this is largely due to system environmental parameters and user defined equipment choices. Things such as CPU, Cooling Capacity, Operating System, Memory type, Hard Drive type, System Usage and the like all go in to setting the Bios up correctly. The best advice is to thoroughly read the owners manual on this topic and try different settings only as as required. I will, however, attempt to guide you through the basics that I feel are necessary for system stability and system set up. A good rule of thumb is to disable what is not needed for system operation as this will increase boot sequence time, however, do not disable anything if you do not know what it is your disabling or if you are unsure- leave the setting to it's default setting.

A word of advice on using the system Bios and O/S installation. Preparation with concern to the Asus system Bios has a few settings that can only be enabled or disabled BEFORE the system O/S is installed to your hard drive(s). Please make sure you have done the proper research and adjusted accordingly before hand as you will not be able to change certain settings once an O/S has been installed.

Description of the absolutes-APIC and ACPI: Briefly, APIC is the new IRQ steering method for newer Operating Systems and it allows the O/S full access to all IRQ's, Windows 2000 and XP users may use APIC,  Windows 9X users may not.

A word of caution: this motherboard supports the new APIC standard which is for use with Operating Systems that no longer make use of DOS. By default APIC is set to the "ON" position from within the system BIOS. That is to say- users of Windows; ME, 98 SE, 98, and 95 - CANNOT USE THE APIC feature. These O/S users must FIRST DISABLE APIC from within the system BIOS before installing the Operating System.  APIC, once installed with ANY Operating System cannot be disabled, the same applies to ACPI power management. To disable or Enable APIC or ACPI correctly on a system with an O/S already installed, the system O/S must be reinstalled.

APIC has been reported by some users to degrade system performance on certain systems, disabling APIC should not cause any problems and may increase performance on select machines, provided the above is followed. However, more IRQ's will be shared with out using APIC. APIC has also been known to cause audio problems with concern to the NForce onboard audio system in certain systems. From my experience XP users have reportedly  had fairly good luck with APIC enabled, Windows 2000 users, such as myself, have had to disable APIC due to audio problems with APIC enabled. This required an O/S re-install. The APIC settings parameter is available from the Advanced Bios Settings menu. The ACPI settings parameter can be found in the Power Management settings page.

CPU multiplier and memory settings, what are they?

Upon first boot up into the system Bios a new user will be faced with this question and although it may at first seem complicated it is really quite simple. This motherboard will be at the default settings which will be set to 100mhz speeds or the lowest possible for first boot. The reason for this is that Asus feels that this is best for guaranteed boot up. This is not a problem as we have the ability to adjust the settings for this.

The formula for configuring your CPU and Memory correctly are as follows- The CPU default multiplier speed multiplied by the Memory sub-systems speed setting (FSB). For example: an AMD Athlon XP Barton 2500 has a default multiplier of 11, lets say for example we are using DDR memory rated at a speed of "PC-2700" or 166mhz. The formula goes like this- CPU multiplier (11) multiplied by the memory speed (166) or 11x166=1826mhz. This formula is universal, all that is required are knowing what the CPU and Memory's speed rating are. Recommended setting are the defaults.

Default Multiplier settings for AMD processors - General

Below you will find a chart containing the most recent AMD processors available, remember when the suggestion was made previously to write down your hardware specifics- this is an example of why. Search through the below list and identify your CPU, then use the information contained in the chart to set your BIOS parameters correctly. Remember, true FSB settings are actually half the rating when setting FSB parameters in the System bios. That is- as per the listings from the chart below. (please see the memory section for more information)

Core OPN Model Operating Freq.(MHz) Clock Mult. Nominal Voltage Max Die Temp. FSB Freq.(MHz) L2 Cache

Model 10

AXDA3200DKV4E 3200+ 2200MHz 11x 1.65V 85 C 400MHz 512KB
AXDA3000DKV4E 3000+ 2100MHz 10.5x
AXDA3000DKV4D 3000+ 2167MHz 13x 333MHz
AXDA2800DKV4D 2800+ 2083MHz 12.5x
AXDA2600DKV4D 2600+ 1917MHz 11.5x
AXDA2500DKV4D 2500+ 1833MHz 11x
Model 8
AXDA2700DKV3D 2700+ 2167MHz 13x 1.65V 85 C 333MHz 256KB
AXDA2600DKV3D 2600+ 2083MHz 12.5x
AXDA2600DKV3C 2600+ 2133MHz 16x 266MHz
AXDA2400DKV3C 2400+ 2000MHz 15x
AXDA2400DUV3C 2400+ 2000MHz 15x 1.60V
AXDA2200DUV3C 2200+ 1800MHz 13.5x
AXDA2200DKV3C 2200+ 1800MHz 13.5x 1.65V
AXDA2100DUT3C 2100+ 1733MHz 13x 1.60V 90 C
AXDA2000DUT3C 2000+ 1667MHz 12.5x
AXDA2000DKT3C 2000+ 1667MHz 12.5x 1.65V
AXDA1900DLT3C 1900+ 1600MHz 12x 1.50V
AXDA1800DUT3C 1800+ 1533MHz 11.5x 1.60V
AXDA1800DLT3C 1800+ 1533MHz 11.5x 1.50V
AXDA1700DUT3C 1700+ 1467MHz 11x 1.60V
AXDA1700DLT3C 1700+ 1467MHz 11x 1.50V
AXDA1600DUT3C 1600+ 1400MHz 10.5x 1.60V
Model 6
AX2100DMT3C 2100+ 1733MHz 13x 1.75V 90 C 266MHz 256KB
AX2000DMT3C 2000+ 1667MHz 12.5x
AX1900DMT3C 1900+ 1600MHz 12x
AX1800DMT3C 1800+ 1533MHz 11.5x
AX1700DMT3C 1700+ 1467MHz 11x
AX1600DMT3C 1600+ 1400MHz 10.5x
AX1500DMT3C 1500+ 1333MHz 10x


OPN Example of an AMD Athlon XP Processor
AXDA 3200 D K V 4 E
AXDA Architecture Segment:
    AXDA = AMD Athlon™ XP Processor ("Barton"/"Thoroughbred")
    AX = AMD Athlon™ XP Processor ("Palomino")
3200 Model Number: 1500+ to 3200+ and above
D Package Type: D = OPGA
K Operating Voltage:
    L = 1.50V
    U = 1.60V
    K = 1.65V
    M = 1.75V
V Die Temperature:
    T = 90 Degrees Celsius
    V = 85 Degrees Celsius
4 Size of L2 Cache:
    3 = 256KB
    4 = 512KB
E Max FSB:
    C = 266MHz
    D = 333MHz
    E = 400MHz

Note: The difference between a Barton core and a Standard XP are identifiable by the difference in the CPU die size- the Barton die is rectangular (and larger) the XP is more squarish. (this is due to the additional cache) The above chart is not indicative of real world performance as many CPU's will perform far better than the rated speed when bench testing.

CPU multiplier settings, FSB (Front Side Buss) and Percentage settings

Here-in lie the settings for your CPU, Memory and percentage range between the two. These settings are of the utmost importance and have the greatest affect on system performance. Settings that are too low will result in sub-standard performance, settings that are to high will result in a system that will no longer boot and or cause data corruption and possible CPU damage. A brief description of settings necessary for correct system operation are as follows-

When first you open the menu to the Advanced Chipset Control you will see an entire page of settings, for our purposes we will only be listing those that are necessary for correct system operation.

The numbered settings listed below are contained from with-in the BIOS Advanced Chipset menu.

1- CPU External Frequency- this parameter sets the CPU external speed or commonly known as the front side buss speed (FSB) Settings for this are defined by the follow settings. Available choices are 100, 133, 166, 200, or increments of 1mhz to 300 MHz depending on system settings and Bios.

2- CPU Frequency Multiple Setting- this parameter allows for setting the desired CPU multiplier setting from the below - AUTO, Optimal or Aggressive. AUTO will cause the motherboard to set according to the CPU fid. (an identifier chip contained with in the CPU)   Optimal, this setting will allow the motherboard to set according to what Asus has programmed into the system Bios for your particular CPU. Aggressive, this setting allows the end-user (you) to set the CPU multiplier to your preference. (see below)

3- CPU Frequency Multiple- This setting is only available if the user has selected from the above settings- Optimal or Aggressive. What this setting does is to allow a user to set the CPU multiplier to the users desired multiplier setting.

4- System Performance- This setting sets the overall system parameters for the available settings contained with-in the Advanced Chipset Control area. Available choices are Optimal, Aggressive and User defined- When set to Optimal this setting allows the motherboard to set according to a pre-programmed Asus Bios setting according to your hardware. Aggressive- this setting allows a more aggressive Asus setting to set the parameters. User defined allows a user full access to all settings.*

5- CPU Interface-This setting allows the user to select to enable the Memory Frequency setting- Settings are- Optimal and Aggressive. Optimal-this setting allows the motherboard to control the memory speed. Aggressive- this setting allows the user to set the below field to preference.

6- Memory Frequency- a percentage rate setting - or the difference between CPU to Memory speed. This allows a user to select various memory to CPU settings according to your FSB, AUTO- as the motherboard's Bios determines or by SPD (serial presence detect- a chip contained with in your memory module). It seems that the best setting is 100% percent for best system stability. (this is especially true with Dual Channel operation)

7- Spread Spectrum*- This setting affects the way the perspective memory and system controllers interact. This setting is only available when the above settings are ALL set to Default or Optimal. It is advisable to change this setting first because of the aforementioned reason. Change this setting parameter to 0 for both fields, this will aid in system stability. (*for users with system clock problems this setting greatly helps) This setting can also help attain a bit higher memory speeds.

8- AGP settings- AGP settings are very straight forward and will automatically set to the default ratings of your graphics card that you have chosen to install. However, the following adjustment is advised- I believe one should set the AGP multiplier to the default of 66mhz. The reason for this is that the system buss is dynamic by nature and may have minor changes that affect graphics quality at certain times. By setting this Bios setting to 66mhz this setting will remain true or be "hard locked" to this speed setting and there-by unaffected by system buss dynamics. Additionally, the AGP aperture size should be set to 1/4th of total system memory or no less than 48. ATI recommends 64 for their products, and most users set to 64 or 128. No real performance gains are seen by setting higher than this at the present time.

Overclocking- Overclocking refers to the ability of setting the above parameters to beyond the ratings issued by the manufacture. It is not advisable, will void your warranty, and is definitely not for the new system builder. Many, many things go into, and are required for Overclocking, and this guide is not meant for covering ANY aspect of Overclocking.

Flashing the System BIOS- Flashing the System Bios is a way for the manufacture to update your motherboards sub-system, or by laymen's terms- the control center for the motherboard. This is generally easy to do, but if done incorrectly can render your system unusable. Remember, there are TWO different A7N8X versions- revision 1 series,  and revision 2 series, the BIOS' are not inter-changeable.

If you are unsure of how to do this it is advisable that you allow someone with the proper experience to perform the BIOS update for you.

There are two ways to flash the System Bios- One is from with-in the Windows environment using the supplied ASUS flashing utility, or secondly- AWDFLASH.  Method of Flashing is not overly important, as either of the two will work. New users would be best advised to use the supplied ASUS flashing utility program contained on the CD you received with your mother board packaging (you must first install this utility to use it) as it  pretty much performs the flash procedure for you. I will briefly cover the two mentioned.

When first using the Windows based flashing utility it will want to first update itself- let it - it will then announce that it must re-start itself- let it, then re-open the utility and select "auto-search" from the drop down box, this allows the utility to use your internet connection to search for the latest BIOS version from the best location automatically. This will take a few minuets. After the utility performs the search it will inform you of this, the location and the BIOS version found and ask you what you wish to do. From the drop down menu you may select the procedure you wish the utility to perform for example- save to disc, install, etc. If you choose to download and save the Bios to disc you will now have to "flash" the Bios manually- you may still use the utility to do this (see the drop down menu from the utility) or you may directly choose to have the utility "self-install" the newly down-loaded Bios, either way, after this procedure a re-boot is required.

Another way to flash the system BIOS is using the AWDFLASH. utility. This is a utility that must be installed to a blank floppy disc and used at the boot sequence while pressing alt-f2. The floppy disc must be inserted to the floppy drive before system start up. As well the appropriate BIOS image file must also be contained and unzipped on the same floppy disc. AWDFLASH. will ask you for the correct BIOS image file, if only one BIOS file or "image" is located on your floppy disc you may select it for the AWDFLASH. utility to install, if more than one you will have to choose. After installation the utility will test itself to ensure that the installation operation succeeded. Reboot when prompted to do so. Before the system restarts please remove the floppy disc from your floppy drive.

Presently, the preferred Bios for the revision two motherboards are the 1004 and 1005 issue. And of course the much desired UBER 1004 and 1005 series of Bios'. (UBER refers to a Bios that has been modified to perform better than it's factory counter part)

NOTE: It is absolutely imperative that no power interruption, or system interruption occurs while FLASHING the SYSTEM BIOS. If this occurs your system will be rendered useless. It is also highly advisable to turn off any Anti-Virus protection, and or any other programs that are running before attempting a BIOS flash (Windows based). If you are unsure of this procedure get the appropriate help. NEVER blindly flash ANY BIOS with out first being fully aware of what you are doing. Again, an incorrect BIOS flash will render your system useless if done incorrectly- PLEASE- use extreme caution.